Objective To study the incidence difference between healthy people and patients with malignant tumor, and to discuss the diagnostic value of whole-body ¹⁸F-FDG PET/CT examination on incidental pituitary macroadenomas.

Methods A review analysis was made about the image data of 1830 consecutive subjects with no history of pituitary tumor, including 600 healthy subjects and 1230 patients with known or suspected malignancy who underwent ¹⁸F-FDG PET/CT examination. The uptake intensity was recorded by maximum standardized uptake value(SUV_max) of those unexpected pituitary tumor(shot diameter greater than 1.0 cm)with high uptake. The final diagnosis was based on pathology and a 3-26 months follow-up. Compared the incidence difference between healthy people and patients with malignant tumor by Fisher exact test(SPSS 16.0). Assessed the diagnostic efficacy of PET/CT examination.

Results Pituitary tumor was accidentally discovered in 15 patients (SUV_max varied between 4.2 and 22.2), including 1 metastases SUV_max 19.5 and 14 (0.77%) pituitary macroadenomas; the incidence rate 0.17% (only 1 case was confirmed of pituitary macroadenomas) among the healthy subjects is higher than that of 1.06% (13 cases) among the malignant tumor patients. The sensitivity and accuracy of PET/CT in detecting large pituitary adenomas were 100% and 93.33% respectively.

Conclusions The incidence of pituitary macroadenoma is higher in patients with maligant tumor than that in the healthy controls. PET/CT is of practical significance in the diagnosis of the pituitary macroadenomas.